l am making a nursing diagnoses, can l write there the problem, decreased cardiac output related to increased vascular resistance SECONDARY to hypertension? thnx

l would like to help, but the question is so loosely phrased that it does not really make sense. l am not criticizing you, but simply trying to let u know how impossible it is to formulate a guided answer.
But here goes:

(1) CO has an inverse relationship to TPR. So when CO goes down (typically upon going to sleep for instance, or periods of deep relaxation) then TPR rises. The converse is also true, in that when the body (or mind) is subject to stress -typically after a big heavy meal, or exercising on a treadmill- greater throughput of blood & thus higher CO, is called for, & TPR goes DOWN to facilitate flow, & minimizing the extent to which Mean Arterial Pressure has to rise. (The Mean Pressure Equation, Pm = CO x TPR)

(2) Quite what u mean by ''secondary to hypertension'' is unclear. The above mechanism (para.1) MUST go on & continue operate, both when ''hypertension'' is present or in its absence. That is, whether or not the patient is hypertensive does not make any difference. The brain & nervous control systems still ensure that TPR increases with decreasing CO & vice versa.

So one is not in any way ''secondary'' to the other. They r independent of each other & complementary.
which is why acute hypertension can be fatal. A patient can live with severe hypertension, & can carry on a normal relaxed life. Similarly, a person without hypertension can stand severe stresses. But when a hypertensive is subjected to transient excessive stresses, & the heart is CAPABLE of producing (L. ventricular) pressures to satisfy the body is demand for adequate CO under these conditions, THEN blood vessels rupture.

Do feel free to make a further posting if u need more clarification.